In this work, we present a systematic study of the Marianian (Cambrian Series 2) trilobites from the area between the Totanés and Noez localities (Central Iberian Zone) and their biostratigraphical significance. Two different fossiliferous assemblages were recognized: the first is characterized by the presence of Serrodiscus bellimarginatus, Chelediscus garzoni, Atops calanus, and Pseudatops reticulatus. The second assemblage is composed of Serrodiscus bellimarginatus, Triangulaspis sp., Andalusiana aff. cornuta, Termierella (Brevitermierella) n. sp., and Acanthomicmacca sp., along with brachiopods and a small shelly fauna. These fossil assemblages indicate a late Marianian age in the regional stratigraphic chart for the Cambrian of the Iberian Peninsula, as Serrodiscus, Chelediscus and Pseudatops have been recorded in the upper Marianian stage, and Triangulaspis, Andalusiana, Termierella, Atops and Acanthomicmacca are characteristic of the middle to upper Marianian.

The taxa reviewed herein have a remarkable regional and international correlation potential: Andalusiana and Termierella occur in the Ossa Morena Zone, the Iberian Chains and Morocco; Chelediscus, Triangulaspis, Acanthomicmacca, Atops and Pseudatops have also been recorded from the Ossa Morena Zone, Morocco, Newfoundland, Siberia, and other regions, while Serrodiscus has a worldwide geographic distribution. In addition, the proposal made by the ISCS regarding the assemblage composed of Hebediscus Whitehouse, Calodiscus Howell, Serrodiscus and Triangulaspis as a potential marker for the base of the Cambrian Stage 4 may imply that the upper Marianian deposits of this area could be roughly correlated with the base of this stage.